Aerospace Medicine and Biology. A continuing bibliography with indexes

This bibliography lists 244 reports, articles, and other documents introduced into the NASA scientific and technical information system in February 1981. Aerospace medicine and aerobiology topics are included. Listings for physiological factors, astronaut performance, control theory, artificial intelligence, and cybernetics are included

High Fidelity Bioelectric Modelling of the Implanted Cochlea

Cochlear implants are medical devices that can restore sound perception in individuals with sensorineural hearing loss (SHL). Since their inception, improvements in performance have largely been driven by advances in signal processing, but progress has plateaued for almost a decade. This suggests that there is a bottleneck at the electrode-tissue interface, which is responsible for enacting the biophysical changes that govern neuronal recruitment. Understanding this interface is difficult because the cochlea is small, intricate, and difficult to access. As such, researchers have turned to modelling techniques to provide new insights. The state-of-the-art involves calculating the electric field using a volume conduction model of the implanted cochlea and coupling it with a neural excitation model to predict the response. However, many models are unable to predict patient outcomes consistently. This thesis aims to improve the reliability of these models by creating high fidelity reconstructions of the inner ear and critically assessing the validity of the underlying and hitherto untested assumptions. Regarding boundary conditions, the evidence suggests that the unmodelled monopolar return path should be accounted for, perhaps by applying a voltage offset at a boundary surface. Regarding vasculature, the models show that large modiolar vessels like the vein of the scala tympani have a strong local effect near the stimulating electrode. Finally, it appears that the oft-cited quasi-static assumption is not valid due to the high permittivity of neural tissue. It is hoped that the study improves the trustworthiness of all bioelectric models of the cochlea, either by validating the claims of existing models, or by prompting improvements in future work. Developing our understanding of the underlying physics will pave the way for advancing future electrode array designs as well as patient-specific simulations, ultimately improving the quality of life for those with SHL

Brain anatomical correlates of perceptual phonological proficiency and language learning aptitude

The present dissertation concerns how brain tissue properties reflect proficiency in two aspects of language use: the ability to use tonal cues on word stems to predict how words will end and the aptitude for learning foreign languages. While it is known that people differ in their language abilities and that damage to brain tissue cause loss of cognitive functions, it is largely unknown if differences in language proficiencies correlate with differences in brain structure. The first two studies examine correlations between cortical morphometry, i.e. the thickness and surface area of the cortex, and the degree of dependency on word accents for processing upcoming suffixes in Swedish native speakers. Word accents in Swedish facilitate speech processing by having predictive associations to specific suffixes, (e.g. fläckaccent1+en ‘spot+singular’, fläckaccent2+ar ‘spot+plural’). This use of word accents, as phonological cues to inflectional suffixes, is relatively unique among the world’s languages. How much a speaker depends on word accents in speech processing can be measured as the difference in response time (RT) between valid and invalid word accent-suffix combinations when asked to identify the inflected form of a word. This can be thought of as a measure of perceptual phonological proficiency in native speakers. Perceptual phonological proficiency is otherwise very difficult to study, as most phonological contrasts are mandatory to properly interpret the meaning of utterances. Study I compares the cortical morphometrical correlates in the planum temporale and inferior frontal gyrus pars opercularis in relation to RT differences in tasks involving real words and pseudowords. We found that thickness of the left planum temporale correlates with perceptual phonological proficiency in lexical words but not pseudowords. This could implicate that word accents are part of full-form representations of familiar words. Moreover, for pseudowords but not lexical words, the thickness of the inferior frontal gyrus pars opercularis correlates with perceptual phonological proficiency. This association could reflect a greater importance for decompositional analysis in which word accents are part of a set of rules listeners need to rely on during processing of novel words. In study II, the investigation of the association between perceptual phonological proficiency in real words with cortical morphometry is expanded to the entire brain. Results show that cortical thickness and surface area of anterior temporal lobe areas, known constituents of a ventral sound-to-meaning language-processing stream is associated with greater perceptual phonological proficiency. This is consistent with a role for word accents in aiding putting together the meaning of or accessing a whole word representation of an inflected word form. Studies III and IV investigate the cortical morphometric associations with language learning aptitude. Findings in study III suggest that aptitude for grammatical inferencing, i.e. the ability to analytically discern the rules of a language, is associated with cortical thickness in the left inferior frontal gyrus pars triangularis. Furthermore, pitch discrimination proficiency, a skill related to language learning ability, correlates negatively with cortical thickness in the right homologue area. Moreover, study IV, using improved imaging techniques, reports on a correlation between vocabulary learning aptitude and cortical surface area in the left inferior precuneus as well as a negative correlation between diffusional axial kurtosis and phonetic memory in the left arcuate fasciculus and subsegment III of the superior longitudinal fasciculus. However, the finding correlation between cortical thickness and grammatical inferencing skill from study III was not replicated in study IV.Taken together, the present dissertation shows that differences in some language proficiencies are associated with regionally thicker or larger cortex and more coherent white matter tracts, the nature and spatial locus of which depend on the proficiency studied. The studies add to our understanding of how language proficiencies are represented in the brain’s anatomy

Aerospace Medicine and Biology: A cumulative index to the 1982 issues

This publication is a cumulative index to the abstracts contained in the Supplements 229 through 240 of Aerospace Medicine and Biology: A continuing Bibliography. It includes three indexes: subject, personal author, and corporate source

Advances in Computer Science and Engineering

The book Advances in Computer Science and Engineering constitutes the revised selection of 23 chapters written by scientists and researchers from all over the world. The chapters cover topics in the scientific fields of Applied Computing Techniques, Innovations in Mechanical Engineering, Electrical Engineering and Applications and Advances in Applied Modeling

Aerospace Medicine and Biology: A cumulative index to the 1980 issues

A cumulative index to the abstracts contained in the Supplements 203 through 214 of Aerospace Medicine and Biology: A Continuing Bibliography is presented. It includes three indexes--subject, personal author, and corporate source

Aerospace Medicine and Biology: A cumulative index to the 1981 issues

The aeromedical research reported considers the safety of the human component in manned space flight. The effects of spacecraft environment, radiation and weightlessness on human biological and psychological processes are covered

Aerospace medicine and biology: A cumulative index to the 1986 issues (supplement 293)

This publication is a cumulative index to the abstracts contained in the Supplements 281 through 292 of Aerospace Medicine and Biology: A Continuing Bibliography. It includes seven indexes - subject, personal author, corporate source, foreign technology, contract number, report number, and accession number

Aerospace Medicine and Biology: A cumulative index to a continuing bibliography

This publication is a cumulative index to the abstracts contained in Supplements 138 through 149 of AEROSPACE MEDICINE AND BIOLOGY: A CONTINUING BIBLIOGRAPHY. It includes three indexes -- subject, personal author, and corporate source